Neurons under study to tackle ailments better

defects in the growth process of neurons often underlie brain or nerve diseases, such as Alzheimer's disease or multiple sclerosis. Scientists from the Flanders Interuniversity Institute for Biotechnology and the Katholieke Universiteit Leuven, led by Bassem Hassan, have achieved a major step in unraveling the growth process of axons, the offshoots of neurons.

They have identified the jnk, wnt and fgf signalling cascades as the most important actors. Their research shows that the growth of axons and the activity of neurons are completely independent of each other. This new finding can lead to better understanding of a variety of nerve diseases.

Hassan used fruit fly (Drosophila melanogaster) as a model for his research. Axon growth is a complicated process and it involves growth, orientation and recognition.To bring clarity to this complex organisation, Mohammed Srahna and his colleagues, led by Hassan, have been studying the Dorsal Cluster Neurons (dcn), a group of cells in the fruit fly's brain. The dcn belong to the visual system of the adult fruit fly and stimulate the visual cortex. The axons of the dcn form a very stereotypical connection pattern. This well-ordered pattern gave the researchers the perfect starting point for studying the influence of various genes on the axon growth process.

The researchers found that axon growth is mediated by an interaction among three signal cascades: wnt, fgf and jnk. jnk is necessary for stimulating the growth of axons. wnt activates jnk and fgf inactivates jnk, so the right balance between wnt and fgf provides for a precise regulation of the growth of neurons. Axonal growth turns out to be completely independent of neuronal activity. This finding brings greater clarity to the axon's growth process.